Slip rings, also referred to as rotary electrical interfaces, rotating
electrical connectors, swivels, collectors, or electrical rotary joints,
are electromechanical devices that allow the transmission of power from
a stationary object to a rotating object, and are commonly found in
electric motors, electrical generators for AC systems, alternators, and
wind turbines. Traditionally, slip rings have used carbon brushes (a
high resistance, monolithic brush made from graphite, which sometimes
has added silver or copper). These electrical brushes abrade over time,
creating harmful and conductive carbon dust particles, wearing the
surfaces they run on and requiring frequent maintenance.

To solve this problem, Defense Holdings, Inc (DHi), then operating as
Noesis, Inc., originally developed Metal Fiber Brushes for use on
submarines under the Small Business Independent Research (SBIR) program
working with HiPerCon, LLC, the U.S. Navy, and the University of
Virginia. Metal Fiber Brushes, which gain their name from the fact that
they are constructed of thousands of hair-fine silver alloy fibers
running on their tips, offer significant improvement over carbon brushes
in both data and current transfer, offering extended brush and slip ring
service life of at least twice the service life of carbon brushes, high
current capacity of 250 amps/inch2, and significant decreases in service
acoustic and electrical noise at sliding speeds up to 70 m/second. These
brushes produce 80% less wear debris than solid brushes reducing the
need for expensive maintenance and reducing the potential for shorts and
grounds. HiPerCon’s silver alloy fibers offer significantly better
service life and higher speeds over gold wire slip ring technology at a
considerable price advantage.

HiPerCon is the worldwide exclusive licensee for this technology. DHi is
HiPerCon’s sole distributor for Metal Fiber Brush and slip ring products
including HiPerCon’s line of shaft grounding brushes.

DHi will design, analyze, and develop prototype brush block assemblies
featuring HiPerCon® brand Metal Fiber Brushes’ (MFBs) electrical brush
technology. The intention is to develop a power and data transfer (PDT)
unit with increased reliability suitable for Sikorsky’s HMVS. The HMVS
system represents a significant improvement in the control of vibration
at its source and will enable a smoother helicopter ride with less
weight than conventional vibration treatments. DHi has previously
developed a main rotor de-icing slip ring for Army AATD and Sikorsky,
using HiPerCon’s electrical brushes as a form-fit function retrofit to
an existing UH-60 aircraft de-icing slip ring for laboratory and flight
testing later this year. DHi and HiPerCon will provide additional power
and data brush block assemblies for the aircraft de-icing slip ring
which will be used during HMVS testing to transfer power and data to and
from the HMVS system. DHi and HiPerCon will work with Sikorsky and the
LORD Corporation of Cary, NC to evaluate the technology on the
Sikorsky/LORD Active Rotor Component Demonstrator.

DHi and HiPerCon will improve existing Metal Fiber Brushes slip ring
designs, update existing failure modes and effects analyses, fabricate
several prototypes to support ground testing this fall, flight testing
in early 2012, and perform basic tests on these prototypes.

Rich Martin On Power and Data Transfer Units

Rich Martin, Defense Holdings, Inc’s President and CEO stated, “We
strongly believe that our Power and Data Transfer Units (PDTs) using
HiPerCon’s amazing Metal Fiber Brush (MFB) technology provide a
one-of-a-kind slip ring solution to the combined challenges of high
power / high data transfer rates across a rotating interface with low
maintenance, long life and high reliability. Our PDTs build on lessons
learned from our successes in the application of slip rings featuring
Metal Fiber Brushes in nuclear submarines, fixed and rotary wing
aircraft, and wind turbines. It is clear that the ability of HiPerCon
brand brushes to overcome the limitations of carbon brushes and
carbon-metallic brushes is a game-changer for those who require long
electrical brush life, high reliability and minimal conductive wear
debris.”

Founded in 1994 and originally operated as Noesis, Inc., DHi is a
privately-held, service-disabled, veteran-owned, minority-owned, small
business. DHi has been ISO 9001 registered since 2003 and has received
awards from the federal government for outstanding technical innovation
and performance. DHi is based in Manassas Park, VA with other facilities
in Charlottesville, VA and Trenton, NC. DHi works with customers
worldwide to overcome the limitations of conventional carbon and
carbon-metallic brushes and slip ring systems in a wide variety of
applications.

Sikorsky Aircraft Corp., based in Stratford, Conn., is a world leader in
helicopter design, manufacture and service. United Technologies Corp.,
based in Hartford, Conn., provides a broad range of high technology
products and support services to the aerospace and building systems
industries.

The views and conclusions contained in this document are those of DHi
and should not be interpreted as representing the official policies,
either expressed or implied, of the Aviation Applied Technology
Directorate or the U.S. Government. The U.S. Government is authorized to
reproduce and distribute reprints for Government purposes
notwithstanding any copyright notation thereon.